The U.S. Air Force's mysterious unmanned space plane, the X-37B, is about to come back to Earth after more than two years in orbit on a mission the military won't tell us much about. ... [additional details]

The U.S. space shuttle program retired in 2011, leaving American astronauts to hitchhike into orbit. But after three long years, NASA's successor is almost ready to make an entrance. ... [additional details]

NBC News veteran John Palmer -- who worked the White House beat during two presidential administrations and anchored the network's initial coverage of the space shuttle Challenger disaster -- died Saturday, the network announced. ... [additional details]